Heat a large frying pan with 2 tablespoons of olive oil. Add the sliced peppers and onions and sauté until the onions are slightly golden.
Add tomatoes, capers and spices and continue sauté until the tomatoes soften completely; this will take a few minutes, about 10 minutes or so.
When the sauce has thickened add the chopped parsley, another clove of garlic chopped and a little drizzle of olive oil.
Serve hot or cold.